The present invention relates to knives and bayonets having integral blade and tang portions with a handle portion covering the tang and secured by a screw and nut. More particularly, the invention relates to improved means for incorporating a threaded fastener into a knife or bayonet to releasably secure an integral blade and tang in assembled relation with a handle.
U.S. Patent No. discloses a fixed blade knife wherein the head of a machine screw is placed in a slot formed in one end of a tang with a blade extending integrally from the opposite end. The threaded portion of the screw extends through a narrower portion of the slot. A stamping or pressing operation flattens the head of the screw to substantially the same thickness as the tang, an operation which, in effect, makes the screw physically integral with the tang. Although this arrangement represented an improvement in manufacturing technique over previous methods of securing an integral blade and tang to a handle piece, it has been found that under conditions of severe use, where high loads are placed on the blade and transmitted to the tang, the screw is subject to cracking or breaking. Because the screw head is essentially integral with the tang, a defective screw cannot be replaced, thus rendering the entire knife, with the possible exception of the handle piece, useless.
It is a principal object of the present invention to provide means for and methods of releasably retaining an integral knife blade and tang in assembled relation with a handle piece of a fixed blade knife or bayonet.
Another object is to provide a knife having a slotted tang extending from a blade wherein a two-piece threaded fastener is engaged with the tang and a handle in a manner which facilitates field repair in the event of failure of the fastener.
A further object is to provide a novel and improved fixed blade knife, which may be fitted for use as a bayonet, having a blade with integral tang and a handle piece which are releasably held in assembled relation by a two-piece threaded fastener, and methods of fabricating and assembling such knives, wherein damaged portions of the fastener may be easily replaced in the original blade-tang and handle piece.
Additional objects will in part be obvious and in part appear hereinafter.
In accordance with the foregoing objects, the invention contemplates a fixed blade knife comprising two parts, namely, an integral blade and tang, contiguous along a linear axis, formed from a single piece of stainless steel or other suitable metal, and a handle, preferably molded from a suitable plastic. The tang has a constant length, width and thickness, adjoining the blade at a stepped shoulder providing an abutment surface for the handle in the assembled relation of the two parts. At the end opposite its integral connection to the blade, termed the terminal end, a slot is cut into the tang, extending into the terminal end, symmetrical to the longitudinal axis of the tang. The slot includes a first portion, having a first width and extending into the terminal end for a first distance, and a second portion, extending having a second width, greater than the first width, from the first portion for a second distance.
The blade/tang and handle pieces are placed in assembled relation by passing the tang into a through opening in the handle, and are releasably retained in this relation by a two-piece threaded fastener, i.e., a machine screw and a nut. The nut has an outer surface which is cylindrical with opposite sides flattened to lie in planes spaced by a distance equal to or slightly less than the second width of the slot in the tang, permitting the nut to be laterally inserted into the second portion of the slot. The screw which mates with the threaded, through opening in the nut has a threaded portion of first diameter, equal to or slightly less than the first width of the slot, and a head of second diameter, larger than the first diameter. The handle piece has a through, longitudinal opening extending from a proximal to a distal end. The cross-sectional shape of the opening at the distal end is circular with rectangular portions on opposite sides (this shape being termed for convenience a xe2x80x9ckeyholexe2x80x9d shape) and extends in this shape for a distance at least equal to the length of the tang. The keyhole shaped opening is adjoined by a first, cylindrical opening having a diameter equal to or slightly less than the first diameter and a length less than the length of the threaded portion of the screw. The first cylindrical opening is adjoined by a second, cylindrical opening having a diameter equal to or slightly less than the second diameter, thus being of a size to contain the screw head.
In assembly, the nut is placed in the second portion of the tang slot with the threaded opening in the nut substantially aligned with the longitudinal axis of the slot; the flat sides of the nut will be closely retained between opposing sides of the slot. The terminal end of the tang is then inserted into the distal end of the opening in the handle piece, where the rounded sides of the nut and marginal portions along each side of the tang will be closely surrounded by the keyhole shaped opening. The tang is advanced until the distal end of the handle piece contacts the stepped shoulder where the blade and tang are integrally joined, with the entire tang being positioned within the handle piece. The threaded end of the screw is then advanced through the cylindrical openings in the proximal end of the handle and threaded into the nut. A screwdriver or other suitable tool is used to tighten the screw, thereby retaining the blade/tang and handle pieces in assembled relation. If either or both parts of the threaded fastener become damaged or broken, the screw is removed, the blade/tang and handle disassembled, and the damaged portion(s) discarded and replaced, followed by assembling the pieces again as described above.
The foregoing and other features of structure and steps of fabrication and assembly of the invention will be more readily understood and fully appreciated from the following detailed disclosure, taken in conjunction with the accompanying drawings.